Although Fungi were once considered to be part of the plant kingdom, most experts now consider them to be a separate Kingdom or phylum. There are estimated to be over 100,000 different fungi, most of which form only tiny threads (Hypha) that can only be seen through a microscope.

Of these, about 20,000 are considered to be high fungi or macro fungi, i.e. those that produce visible fruiting bodies. Only these are of any interest to the fungi enthusiast and covered in any detail, most of which belong to the subdivision Ascomycotina and Basidiomycotina.